ceph/src/boost/boost/asio/basic_deadline_timer.hpp

   1 //
   2 // basic_deadline_timer.hpp
   3 // ~~~~~~~~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2020 Christopher M. Kohlhoff (chris at kohlhoff dot com)
   6 //
   7 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   9 //
  10
  11 #ifndef BOOST_ASIO_BASIC_DEADLINE_TIMER_HPP
  12 #define BOOST_ASIO_BASIC_DEADLINE_TIMER_HPP
  13
  14 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  15 # pragma once
  16 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  17
  18 #include <boost/asio/detail/config.hpp>
  19
  20 #if defined(BOOST_ASIO_HAS_BOOST_DATE_TIME) \
  21   || defined(GENERATING_DOCUMENTATION)
  22
  23 #include <cstddef>
  24 #include <boost/asio/any_io_executor.hpp>
  25 #include <boost/asio/detail/deadline_timer_service.hpp>
  26 #include <boost/asio/detail/handler_type_requirements.hpp>
  27 #include <boost/asio/detail/io_object_impl.hpp>
  28 #include <boost/asio/detail/non_const_lvalue.hpp>
  29 #include <boost/asio/detail/throw_error.hpp>
  30 #include <boost/asio/error.hpp>
  31 #include <boost/asio/execution_context.hpp>
  32 #include <boost/asio/time_traits.hpp>
  33
  34 #include <boost/asio/detail/push_options.hpp>
  35
  36 namespace boost {
  37 namespace asio {
  38
  39 /// Provides waitable timer functionality.
  40 /**
  41  * The basic_deadline_timer class template provides the ability to perform a
  42  * blocking or asynchronous wait for a timer to expire.
  43  *
  44  * A deadline timer is always in one of two states: "expired" or "not expired".
  45  * If the wait() or async_wait() function is called on an expired timer, the
  46  * wait operation will complete immediately.
  47  *
  48  * Most applications will use the boost::asio::deadline_timer typedef.
  49  *
  50  * @par Thread Safety
  51  * @e Distinct @e objects: Safe.@n
  52  * @e Shared @e objects: Unsafe.
  53  *
  54  * @par Examples
  55  * Performing a blocking wait:
  56  * @code
  57  * // Construct a timer without setting an expiry time.
  58  * boost::asio::deadline_timer timer(my_context);
  59  *
  60  * // Set an expiry time relative to now.
  61  * timer.expires_from_now(boost::posix_time::seconds(5));
  62  *
  63  * // Wait for the timer to expire.
  64  * timer.wait();
  65  * @endcode
  66  *
  67  * @par
  68  * Performing an asynchronous wait:
  69  * @code
  70  * void handler(const boost::system::error_code& error)
  71  * {
  72  *   if (!error)
  73  *   {
  74  *     // Timer expired.
  75  *   }
  76  * }
  77  *
  78  * ...
  79  *
  80  * // Construct a timer with an absolute expiry time.
  81  * boost::asio::deadline_timer timer(my_context,
  82  *     boost::posix_time::time_from_string("2005-12-07 23:59:59.000"));
  83  *
  84  * // Start an asynchronous wait.
  85  * timer.async_wait(handler);
  86  * @endcode
  87  *
  88  * @par Changing an active deadline_timer's expiry time
  89  *
  90  * Changing the expiry time of a timer while there are pending asynchronous
  91  * waits causes those wait operations to be cancelled. To ensure that the action
  92  * associated with the timer is performed only once, use something like this:
  93  * used:
  94  *
  95  * @code
  96  * void on_some_event()
  97  * {
  98  *   if (my_timer.expires_from_now(seconds(5)) > 0)
  99  *   {
 100  *     // We managed to cancel the timer. Start new asynchronous wait.
 101  *     my_timer.async_wait(on_timeout);
 102  *   }
 103  *   else
 104  *   {
 105  *     // Too late, timer has already expired!
 106  *   }
 107  * }
 108  *
 109  * void on_timeout(const boost::system::error_code& e)
 110  * {
 111  *   if (e != boost::asio::error::operation_aborted)
 112  *   {
 113  *     // Timer was not cancelled, take necessary action.
 114  *   }
 115  * }
 116  * @endcode
 117  *
 118  * @li The boost::asio::basic_deadline_timer::expires_from_now() function
 119  * cancels any pending asynchronous waits, and returns the number of
 120  * asynchronous waits that were cancelled. If it returns 0 then you were too
 121  * late and the wait handler has already been executed, or will soon be
 122  * executed. If it returns 1 then the wait handler was successfully cancelled.
 123  *
 124  * @li If a wait handler is cancelled, the boost::system::error_code passed to
 125  * it contains the value boost::asio::error::operation_aborted.
 126  */
 127 template <typename Time,
 128     typename TimeTraits = boost::asio::time_traits<Time>,
 129     typename Executor = any_io_executor>
 130 class basic_deadline_timer
 131 {
 132 public:
 133   /// The type of the executor associated with the object.
 134   typedef Executor executor_type;
 135
 136   /// Rebinds the timer type to another executor.
 137   template <typename Executor1>
 138   struct rebind_executor
 139   {
 140     /// The timer type when rebound to the specified executor.
 141     typedef basic_deadline_timer<Time, TimeTraits, Executor1> other;
 142   };
 143
 144   /// The time traits type.
 145   typedef TimeTraits traits_type;
 146
 147   /// The time type.
 148   typedef typename traits_type::time_type time_type;
 149
 150   /// The duration type.
 151   typedef typename traits_type::duration_type duration_type;
 152
 153   /// Constructor.
 154   /**
 155    * This constructor creates a timer without setting an expiry time. The
 156    * expires_at() or expires_from_now() functions must be called to set an
 157    * expiry time before the timer can be waited on.
 158    *
 159    * @param ex The I/O executor that the timer will use, by default, to
 160    * dispatch handlers for any asynchronous operations performed on the timer.
 161    */
 162   explicit basic_deadline_timer(const executor_type& ex)
 163     : impl_(ex)
 164   {
 165   }
 166
 167   /// Constructor.
 168   /**
 169    * This constructor creates a timer without setting an expiry time. The
 170    * expires_at() or expires_from_now() functions must be called to set an
 171    * expiry time before the timer can be waited on.
 172    *
 173    * @param context An execution context which provides the I/O executor that
 174    * the timer will use, by default, to dispatch handlers for any asynchronous
 175    * operations performed on the timer.
 176    */
 177   template <typename ExecutionContext>
 178   explicit basic_deadline_timer(ExecutionContext& context,
 179       typename enable_if<
 180         is_convertible<ExecutionContext&, execution_context&>::value
 181       >::type* = 0)
 182     : impl_(context)
 183   {
 184   }
 185
 186   /// Constructor to set a particular expiry time as an absolute time.
 187   /**
 188    * This constructor creates a timer and sets the expiry time.
 189    *
 190    * @param ex The I/O executor that the timer will use, by default, to
 191    * dispatch handlers for any asynchronous operations performed on the timer.
 192    *
 193    * @param expiry_time The expiry time to be used for the timer, expressed
 194    * as an absolute time.
 195    */
 196   basic_deadline_timer(const executor_type& ex, const time_type& expiry_time)
 197     : impl_(ex)
 198   {
 199     boost::system::error_code ec;
 200     impl_.get_service().expires_at(impl_.get_implementation(), expiry_time, ec);
 201     boost::asio::detail::throw_error(ec, "expires_at");
 202   }
 203
 204   /// Constructor to set a particular expiry time as an absolute time.
 205   /**
 206    * This constructor creates a timer and sets the expiry time.
 207    *
 208    * @param context An execution context which provides the I/O executor that
 209    * the timer will use, by default, to dispatch handlers for any asynchronous
 210    * operations performed on the timer.
 211    *
 212    * @param expiry_time The expiry time to be used for the timer, expressed
 213    * as an absolute time.
 214    */
 215   template <typename ExecutionContext>
 216   basic_deadline_timer(ExecutionContext& context, const time_type& expiry_time,
 217       typename enable_if<
 218         is_convertible<ExecutionContext&, execution_context&>::value
 219       >::type* = 0)
 220     : impl_(context)
 221   {
 222     boost::system::error_code ec;
 223     impl_.get_service().expires_at(impl_.get_implementation(), expiry_time, ec);
 224     boost::asio::detail::throw_error(ec, "expires_at");
 225   }
 226
 227   /// Constructor to set a particular expiry time relative to now.
 228   /**
 229    * This constructor creates a timer and sets the expiry time.
 230    *
 231    * @param ex The I/O executor that the timer will use, by default, to
 232    * dispatch handlers for any asynchronous operations performed on the timer.
 233    *
 234    * @param expiry_time The expiry time to be used for the timer, relative to
 235    * now.
 236    */
 237   basic_deadline_timer(const executor_type& ex,
 238       const duration_type& expiry_time)
 239     : impl_(ex)
 240   {
 241     boost::system::error_code ec;
 242     impl_.get_service().expires_from_now(
 243         impl_.get_implementation(), expiry_time, ec);
 244     boost::asio::detail::throw_error(ec, "expires_from_now");
 245   }
 246
 247   /// Constructor to set a particular expiry time relative to now.
 248   /**
 249    * This constructor creates a timer and sets the expiry time.
 250    *
 251    * @param context An execution context which provides the I/O executor that
 252    * the timer will use, by default, to dispatch handlers for any asynchronous
 253    * operations performed on the timer.
 254    *
 255    * @param expiry_time The expiry time to be used for the timer, relative to
 256    * now.
 257    */
 258   template <typename ExecutionContext>
 259   basic_deadline_timer(ExecutionContext& context,
 260       const duration_type& expiry_time,
 261       typename enable_if<
 262         is_convertible<ExecutionContext&, execution_context&>::value
 263       >::type* = 0)
 264     : impl_(context)
 265   {
 266     boost::system::error_code ec;
 267     impl_.get_service().expires_from_now(
 268         impl_.get_implementation(), expiry_time, ec);
 269     boost::asio::detail::throw_error(ec, "expires_from_now");
 270   }
 271
 272 #if defined(BOOST_ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
 273   /// Move-construct a basic_deadline_timer from another.
 274   /**
 275    * This constructor moves a timer from one object to another.
 276    *
 277    * @param other The other basic_deadline_timer object from which the move will
 278    * occur.
 279    *
 280    * @note Following the move, the moved-from object is in the same state as if
 281    * constructed using the @c basic_deadline_timer(const executor_type&)
 282    * constructor.
 283    */
 284   basic_deadline_timer(basic_deadline_timer&& other)
 285     : impl_(std::move(other.impl_))
 286   {
 287   }
 288
 289   /// Move-assign a basic_deadline_timer from another.
 290   /**
 291    * This assignment operator moves a timer from one object to another. Cancels
 292    * any outstanding asynchronous operations associated with the target object.
 293    *
 294    * @param other The other basic_deadline_timer object from which the move will
 295    * occur.
 296    *
 297    * @note Following the move, the moved-from object is in the same state as if
 298    * constructed using the @c basic_deadline_timer(const executor_type&)
 299    * constructor.
 300    */
 301   basic_deadline_timer& operator=(basic_deadline_timer&& other)
 302   {
 303     impl_ = std::move(other.impl_);
 304     return *this;
 305   }
 306 #endif // defined(BOOST_ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
 307
 308   /// Destroys the timer.
 309   /**
 310    * This function destroys the timer, cancelling any outstanding asynchronous
 311    * wait operations associated with the timer as if by calling @c cancel.
 312    */
 313   ~basic_deadline_timer()
 314   {
 315   }
 316
 317   /// Get the executor associated with the object.
 318   executor_type get_executor() BOOST_ASIO_NOEXCEPT
 319   {
 320     return impl_.get_executor();
 321   }
 322
 323   /// Cancel any asynchronous operations that are waiting on the timer.
 324   /**
 325    * This function forces the completion of any pending asynchronous wait
 326    * operations against the timer. The handler for each cancelled operation will
 327    * be invoked with the boost::asio::error::operation_aborted error code.
 328    *
 329    * Cancelling the timer does not change the expiry time.
 330    *
 331    * @return The number of asynchronous operations that were cancelled.
 332    *
 333    * @throws boost::system::system_error Thrown on failure.
 334    *
 335    * @note If the timer has already expired when cancel() is called, then the
 336    * handlers for asynchronous wait operations will:
 337    *
 338    * @li have already been invoked; or
 339    *
 340    * @li have been queued for invocation in the near future.
 341    *
 342    * These handlers can no longer be cancelled, and therefore are passed an
 343    * error code that indicates the successful completion of the wait operation.
 344    */
 345   std::size_t cancel()
 346   {
 347     boost::system::error_code ec;
 348     std::size_t s = impl_.get_service().cancel(impl_.get_implementation(), ec);
 349     boost::asio::detail::throw_error(ec, "cancel");
 350     return s;
 351   }
 352
 353   /// Cancel any asynchronous operations that are waiting on the timer.
 354   /**
 355    * This function forces the completion of any pending asynchronous wait
 356    * operations against the timer. The handler for each cancelled operation will
 357    * be invoked with the boost::asio::error::operation_aborted error code.
 358    *
 359    * Cancelling the timer does not change the expiry time.
 360    *
 361    * @param ec Set to indicate what error occurred, if any.
 362    *
 363    * @return The number of asynchronous operations that were cancelled.
 364    *
 365    * @note If the timer has already expired when cancel() is called, then the
 366    * handlers for asynchronous wait operations will:
 367    *
 368    * @li have already been invoked; or
 369    *
 370    * @li have been queued for invocation in the near future.
 371    *
 372    * These handlers can no longer be cancelled, and therefore are passed an
 373    * error code that indicates the successful completion of the wait operation.
 374    */
 375   std::size_t cancel(boost::system::error_code& ec)
 376   {
 377     return impl_.get_service().cancel(impl_.get_implementation(), ec);
 378   }
 379
 380   /// Cancels one asynchronous operation that is waiting on the timer.
 381   /**
 382    * This function forces the completion of one pending asynchronous wait
 383    * operation against the timer. Handlers are cancelled in FIFO order. The
 384    * handler for the cancelled operation will be invoked with the
 385    * boost::asio::error::operation_aborted error code.
 386    *
 387    * Cancelling the timer does not change the expiry time.
 388    *
 389    * @return The number of asynchronous operations that were cancelled. That is,
 390    * either 0 or 1.
 391    *
 392    * @throws boost::system::system_error Thrown on failure.
 393    *
 394    * @note If the timer has already expired when cancel_one() is called, then
 395    * the handlers for asynchronous wait operations will:
 396    *
 397    * @li have already been invoked; or
 398    *
 399    * @li have been queued for invocation in the near future.
 400    *
 401    * These handlers can no longer be cancelled, and therefore are passed an
 402    * error code that indicates the successful completion of the wait operation.
 403    */
 404   std::size_t cancel_one()
 405   {
 406     boost::system::error_code ec;
 407     std::size_t s = impl_.get_service().cancel_one(
 408         impl_.get_implementation(), ec);
 409     boost::asio::detail::throw_error(ec, "cancel_one");
 410     return s;
 411   }
 412
 413   /// Cancels one asynchronous operation that is waiting on the timer.
 414   /**
 415    * This function forces the completion of one pending asynchronous wait
 416    * operation against the timer. Handlers are cancelled in FIFO order. The
 417    * handler for the cancelled operation will be invoked with the
 418    * boost::asio::error::operation_aborted error code.
 419    *
 420    * Cancelling the timer does not change the expiry time.
 421    *
 422    * @param ec Set to indicate what error occurred, if any.
 423    *
 424    * @return The number of asynchronous operations that were cancelled. That is,
 425    * either 0 or 1.
 426    *
 427    * @note If the timer has already expired when cancel_one() is called, then
 428    * the handlers for asynchronous wait operations will:
 429    *
 430    * @li have already been invoked; or
 431    *
 432    * @li have been queued for invocation in the near future.
 433    *
 434    * These handlers can no longer be cancelled, and therefore are passed an
 435    * error code that indicates the successful completion of the wait operation.
 436    */
 437   std::size_t cancel_one(boost::system::error_code& ec)
 438   {
 439     return impl_.get_service().cancel_one(impl_.get_implementation(), ec);
 440   }
 441
 442   /// Get the timer's expiry time as an absolute time.
 443   /**
 444    * This function may be used to obtain the timer's current expiry time.
 445    * Whether the timer has expired or not does not affect this value.
 446    */
 447   time_type expires_at() const
 448   {
 449     return impl_.get_service().expires_at(impl_.get_implementation());
 450   }
 451
 452   /// Set the timer's expiry time as an absolute time.
 453   /**
 454    * This function sets the expiry time. Any pending asynchronous wait
 455    * operations will be cancelled. The handler for each cancelled operation will
 456    * be invoked with the boost::asio::error::operation_aborted error code.
 457    *
 458    * @param expiry_time The expiry time to be used for the timer.
 459    *
 460    * @return The number of asynchronous operations that were cancelled.
 461    *
 462    * @throws boost::system::system_error Thrown on failure.
 463    *
 464    * @note If the timer has already expired when expires_at() is called, then
 465    * the handlers for asynchronous wait operations will:
 466    *
 467    * @li have already been invoked; or
 468    *
 469    * @li have been queued for invocation in the near future.
 470    *
 471    * These handlers can no longer be cancelled, and therefore are passed an
 472    * error code that indicates the successful completion of the wait operation.
 473    */
 474   std::size_t expires_at(const time_type& expiry_time)
 475   {
 476     boost::system::error_code ec;
 477     std::size_t s = impl_.get_service().expires_at(
 478         impl_.get_implementation(), expiry_time, ec);
 479     boost::asio::detail::throw_error(ec, "expires_at");
 480     return s;
 481   }
 482
 483   /// Set the timer's expiry time as an absolute time.
 484   /**
 485    * This function sets the expiry time. Any pending asynchronous wait
 486    * operations will be cancelled. The handler for each cancelled operation will
 487    * be invoked with the boost::asio::error::operation_aborted error code.
 488    *
 489    * @param expiry_time The expiry time to be used for the timer.
 490    *
 491    * @param ec Set to indicate what error occurred, if any.
 492    *
 493    * @return The number of asynchronous operations that were cancelled.
 494    *
 495    * @note If the timer has already expired when expires_at() is called, then
 496    * the handlers for asynchronous wait operations will:
 497    *
 498    * @li have already been invoked; or
 499    *
 500    * @li have been queued for invocation in the near future.
 501    *
 502    * These handlers can no longer be cancelled, and therefore are passed an
 503    * error code that indicates the successful completion of the wait operation.
 504    */
 505   std::size_t expires_at(const time_type& expiry_time,
 506       boost::system::error_code& ec)
 507   {
 508     return impl_.get_service().expires_at(
 509         impl_.get_implementation(), expiry_time, ec);
 510   }
 511
 512   /// Get the timer's expiry time relative to now.
 513   /**
 514    * This function may be used to obtain the timer's current expiry time.
 515    * Whether the timer has expired or not does not affect this value.
 516    */
 517   duration_type expires_from_now() const
 518   {
 519     return impl_.get_service().expires_from_now(impl_.get_implementation());
 520   }
 521
 522   /// Set the timer's expiry time relative to now.
 523   /**
 524    * This function sets the expiry time. Any pending asynchronous wait
 525    * operations will be cancelled. The handler for each cancelled operation will
 526    * be invoked with the boost::asio::error::operation_aborted error code.
 527    *
 528    * @param expiry_time The expiry time to be used for the timer.
 529    *
 530    * @return The number of asynchronous operations that were cancelled.
 531    *
 532    * @throws boost::system::system_error Thrown on failure.
 533    *
 534    * @note If the timer has already expired when expires_from_now() is called,
 535    * then the handlers for asynchronous wait operations will:
 536    *
 537    * @li have already been invoked; or
 538    *
 539    * @li have been queued for invocation in the near future.
 540    *
 541    * These handlers can no longer be cancelled, and therefore are passed an
 542    * error code that indicates the successful completion of the wait operation.
 543    */
 544   std::size_t expires_from_now(const duration_type& expiry_time)
 545   {
 546     boost::system::error_code ec;
 547     std::size_t s = impl_.get_service().expires_from_now(
 548         impl_.get_implementation(), expiry_time, ec);
 549     boost::asio::detail::throw_error(ec, "expires_from_now");
 550     return s;
 551   }
 552
 553   /// Set the timer's expiry time relative to now.
 554   /**
 555    * This function sets the expiry time. Any pending asynchronous wait
 556    * operations will be cancelled. The handler for each cancelled operation will
 557    * be invoked with the boost::asio::error::operation_aborted error code.
 558    *
 559    * @param expiry_time The expiry time to be used for the timer.
 560    *
 561    * @param ec Set to indicate what error occurred, if any.
 562    *
 563    * @return The number of asynchronous operations that were cancelled.
 564    *
 565    * @note If the timer has already expired when expires_from_now() is called,
 566    * then the handlers for asynchronous wait operations will:
 567    *
 568    * @li have already been invoked; or
 569    *
 570    * @li have been queued for invocation in the near future.
 571    *
 572    * These handlers can no longer be cancelled, and therefore are passed an
 573    * error code that indicates the successful completion of the wait operation.
 574    */
 575   std::size_t expires_from_now(const duration_type& expiry_time,
 576       boost::system::error_code& ec)
 577   {
 578     return impl_.get_service().expires_from_now(
 579         impl_.get_implementation(), expiry_time, ec);
 580   }
 581
 582   /// Perform a blocking wait on the timer.
 583   /**
 584    * This function is used to wait for the timer to expire. This function
 585    * blocks and does not return until the timer has expired.
 586    *
 587    * @throws boost::system::system_error Thrown on failure.
 588    */
 589   void wait()
 590   {
 591     boost::system::error_code ec;
 592     impl_.get_service().wait(impl_.get_implementation(), ec);
 593     boost::asio::detail::throw_error(ec, "wait");
 594   }
 595
 596   /// Perform a blocking wait on the timer.
 597   /**
 598    * This function is used to wait for the timer to expire. This function
 599    * blocks and does not return until the timer has expired.
 600    *
 601    * @param ec Set to indicate what error occurred, if any.
 602    */
 603   void wait(boost::system::error_code& ec)
 604   {
 605     impl_.get_service().wait(impl_.get_implementation(), ec);
 606   }
 607
 608   /// Start an asynchronous wait on the timer.
 609   /**
 610    * This function may be used to initiate an asynchronous wait against the
 611    * timer. It always returns immediately.
 612    *
 613    * For each call to async_wait(), the supplied handler will be called exactly
 614    * once. The handler will be called when:
 615    *
 616    * @li The timer has expired.
 617    *
 618    * @li The timer was cancelled, in which case the handler is passed the error
 619    * code boost::asio::error::operation_aborted.
 620    *
 621    * @param handler The handler to be called when the timer expires. Copies
 622    * will be made of the handler as required. The function signature of the
 623    * handler must be:
 624    * @code void handler(
 625    *   const boost::system::error_code& error // Result of operation.
 626    * ); @endcode
 627    * Regardless of whether the asynchronous operation completes immediately or
 628    * not, the handler will not be invoked from within this function. On
 629    * immediate completion, invocation of the handler will be performed in a
 630    * manner equivalent to using boost::asio::post().
 631    */
 632   template <
 633       BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code))
 634         WaitHandler BOOST_ASIO_DEFAULT_COMPLETION_TOKEN_TYPE(executor_type)>
 635   BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(WaitHandler,
 636       void (boost::system::error_code))
 637   async_wait(
 638       BOOST_ASIO_MOVE_ARG(WaitHandler) handler
 639         BOOST_ASIO_DEFAULT_COMPLETION_TOKEN(executor_type))
 640   {
 641     return async_initiate<WaitHandler, void (boost::system::error_code)>(
 642         initiate_async_wait(this), handler);
 643   }
 644
 645 private:
 646   // Disallow copying and assignment.
 647   basic_deadline_timer(const basic_deadline_timer&) BOOST_ASIO_DELETED;
 648   basic_deadline_timer& operator=(
 649       const basic_deadline_timer&) BOOST_ASIO_DELETED;
 650
 651   class initiate_async_wait
 652   {
 653   public:
 654     typedef Executor executor_type;
 655
 656     explicit initiate_async_wait(basic_deadline_timer* self)
 657       : self_(self)
 658     {
 659     }
 660
 661     executor_type get_executor() const BOOST_ASIO_NOEXCEPT
 662     {
 663       return self_->get_executor();
 664     }
 665
 666     template <typename WaitHandler>
 667     void operator()(BOOST_ASIO_MOVE_ARG(WaitHandler) handler) const
 668     {
 669       // If you get an error on the following line it means that your handler
 670       // does not meet the documented type requirements for a WaitHandler.
 671       BOOST_ASIO_WAIT_HANDLER_CHECK(WaitHandler, handler) type_check;
 672
 673       detail::non_const_lvalue<WaitHandler> handler2(handler);
 674       self_->impl_.get_service().async_wait(
 675           self_->impl_.get_implementation(),
 676           handler2.value, self_->impl_.get_executor());
 677     }
 678
 679   private:
 680     basic_deadline_timer* self_;
 681   };
 682
 683   detail::io_object_impl<
 684     detail::deadline_timer_service<TimeTraits>, Executor> impl_;
 685 };
 686
 687 } // namespace asio
 688 } // namespace boost
 689
 690 #include <boost/asio/detail/pop_options.hpp>
 691
 692 #endif // defined(BOOST_ASIO_HAS_BOOST_DATE_TIME)
 693        // || defined(GENERATING_DOCUMENTATION)
 694
 695 #endif // BOOST_ASIO_BASIC_DEADLINE_TIMER_HPP